• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.1-8
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• 2016

This study was conducted to investigate the physiological responses of sevenband grouper, Epinephelus septemfasciatus at low temperature condition in winter season. Water temperature was dropped from $12^{\circ}C$ to $5^{\circ}C$ by two different interval (interval I: $-1^{\circ}C/24h$ and interval II: $-1^{\circ}C/8h$). The experimental fishes were exposed for 9 days at each water temperature condition, and were observed survival rate. The blood sample was collected from fishes for analysis of cortisol, glucose, total protein (TP), and electrolytes ($Na^+$, $Cl^-$, $K^+$). Mortality of fish was not observed until $5^{\circ}C$. The mortality (12 individuals) began after 170 h and all fish were death after 174 h in interval I case, whereas the mortality (9 individuals) began after 72 h and all fish were death after 76 h in interval II case. Little different was observed in the physiological responses, but trend was similar between two intervals. The physiological metabolism of plasma cortisol and glucose were increased rapidly, and swimming ability and respiration response was faster at $7^{\circ}C$. This result means that the critical temperature of sevenband grouper was $7^{\circ}C$ at low water temperature condition.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.102-108
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• 2000

This study was carried out to investigate the epidemiological prevalence of diseases from birth to weaning in 66 dairy calves which were delivered from three stock farm in Chonbuk area. We examined body weight gain, incidence rate of diseases and population mortality rate in relation to age, season, environmental temperature and rearing management conditions for one year. The results of this experiment were as follows: Birth weight of dairy calves born of primiparae was lower than those of multiparae. But no significant difference in body weight gain was observable between dairy calves born of primiparae and those of multiparae. Body weight gain of diseased calves was lower than normal calves. Of 66 delivered calves, 34 calves(51.5%) were affected with gastronitestinal and/or respiratory diseases. The prevalence of the diseases were gastrointestinal disease(28.7%), respiratory disease(18.2%), and gastronitestinal and respiratory disease(4.6%). The gastronitestinal disease was occurred contrinually regardless of the season. Whereas all of the respiratory disease were occurred in winter and a change of season(December to April). 68.4% of the gastronitestinal disease, and all of the respiratory disease were occurred at atmospheric temperatures below 1$0^{\circ}C$. 89.5% of the gastronitestinal disease were occurred within 3 weeks old, whereas 50% of the respiratory disease were occurred intensively between 3 weeks and 4 weeks old. Of 66 delivered dairy claves, 2 calves were died(3%) with respriratory disease.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.1007-1012
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• 1996

The purpose of the survey was to understand the field situation on the occurrence of enteric diseases in poultry farms in Korea. During the period from January of 1991 to December, 1992, 279(35.8%) out of 779 farms surveyed experienced the cases of enteritis in their chickens. The farms with diarrheal problems consisted of 157(45.1%) of 348 broiler flock, 28(32.6%) of 86 breeder flock, and 94(27.2%) of 345 layer flock. The main diseases causing enteritis were frequently appeared as infectious bursal disease(27.3%), colibacillosis(22.6%), and coccidiosis(8.6%). Necrotic enteritis(NE) in chicken occurred in 21 farms(2.7%) among 779 farms examined. The outbreaks of NE were divided 4.7% in breeders, 4.0% in broilers, and 0.9% in layers, respectively. NE occurred mainly in the age(71.4%) of 20~30 days and the mortality was varying from 1.4% to 10.0% for broilers, 3.0% for layers and 0.8% for breeders. Seasonal prevalence of NE showed the highest as 52.4% in summer and followed by 33.3% in autumn, 9.5% in spring and 4.5% in winter.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.483-489
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• 2016

The type approval test for USCG Phase II must be satisfied such that living natural biota occupy more than 75 % of whole biota in a test tank. Thus, we harvested a community of natural organisms using a net at Masan Bay (eutrophic) and Jangmok Bay (mesotrophic) during winter season to meet this guideline. Furthermore, cell viability was measured to determine the mortality rate. Based on the organism concentration volume (1 ton) at Masan and Jangmok Bay, abundance of ${\geq}10$ and $<50{\mu}m$ sized organisms was observed to be $4.7{\times}10^4cells\;mL^{-1}$and $0.8{\times}10^4cells\;mL^{-1}$, and their survival rates were 90.4 % and 88.0 %, respectively. In particular, chain-forming small diatoms such as Skeletonema costatum-like species were abundant at Jangmok Bay, while small flagellate ($<10{\mu}m$) and non chain-forming large dinoflagellates, such as Akashiwo sanguinea and Heterocapsa triquetra, were abundant at Masan Bay. Due to the size-difference of the dominant species, concentration efficiency was higher at Jangmok Bay than at Masan Bay. The mortality rate in samples treated by Ballast Water Treatment System (BWMS) (Day 0) was a little lower for samples from Jangmok Bay than from Masan Bay, with values of 90.4% and 93%, respectively. After 5 days, the mortality rates in control and treatment group were found to be 6.7% and >99%, respectively. Consequently, the phytoplankton concentration method alone did not easily satisfy the type approval standards of USCG Phase II ($>1.0{\times}10^3cells\;mL^{-1}$ in 500-ton tank) during winter season, and alternative options such as mass culture and/or harvesting system using natural phytoplankton communities may be helpful in meeting USCG Phase II biological criteria.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.409-422
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• 2022

Two dominant thrips in hot pepper (Capsicum annuum) cultivating in greenhouses are Frankliniella occidentalis and F. intonsa in Korea. This study investigated their overwintering physiology. These two thrips were freeze-susceptible and suppressed the body freezing temperature by lowering supercooling point (SCP) down to -15~-27℃. However, these SCPs varied among species and developmental stages. SCPs of F. occidentalis were -25.7±0.5℃ for adults, -17.2±0.3℃ for pupae, and -15.0±0.4℃ for larvae. SCPs of F. intonsa were -24.0±1.0℃ for adults, -27.0±0.5℃ for pupae, -17.2±0.8℃ for larvae. Cold injuries of both species occurred at low temperature treatments above SCPs. Thrips mortality increased as the treatment temperature decreased and its exposure period increased. F. occidentalis exhibited higher cold tolerance than F. intonsa. In both species, adults were more cold-tolerant than larvae. Two thrips species exhibited a rapid cold hardening because a pre-exposure to 0℃ for 2 h significantly enhanced the cold tolerance to a lethal cold temperature treatment at -10℃ for 2 h. In addition, a sequential exposure of the thrips to decreasing temperatures made them to be acclimated to low temperatures. To investigate the overwintering sites of the two species, winter monitoring of the thrips was performed at the greenhouses. During winter season (November~February), adults of the two species were not captured in outside of the greenhouses. However, F. occidentalis adults were captured to the traps and observed in weeds within the greenhouses. F. occidentalis adults were also emerged from soil samples obtained from the greenhouses during the winter season. F. intonsa adults did not come out from the soil samples at November and December, but emerged from the soil samples obtained after January. To determine the adult emergence due to diapause development, two thrips species were reared under different photoperiods. Adult development occurred in all photoperiod treatments in F. occidentalis, but did not in F. intonsa especially under short periods. Tomato spotted wilt virus, which is transmitted by these two species, was detected in the weeds infested by the thrips during the winter season. These results suggest that F. occidentalis develops on weeds in the greenhouses while F. intonsa undergoes a diapause in the soil during winter.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.2
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• pp.115-132
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• 1992

This study was conducted to clarify the distribution pattern of macrobenthic soft-bottom dwelling animals near the shellfish farming ground in Chinhae Bay, Korea Sampling was seasonally performed with van Veen grab$(0.1m^2)$ from October 1990 to July 1991. Benthic animals collected during the study comprised 107 species which amounted to 6,978 individuals: 52 species from polychaetes$(48.6\%)$, 34 species from crustaceans$(31.8\%),$ 14 species from molluscs$(13.1\%)$ and 7 species from other faunal groups$(6.5\%)$. The dominant species were four polychaetes and one amphipod: Lumbrineis longifolia, Capitella capitate, Mediomastus sp., Sigambra tentaculata and Erictonius pugnax. The study area could be divided into 3 regions based on the faunal similarity which was closely related to the content of organic matter in the surface sediment. The benthic community located near the shellfish farming ground showed large spatial and seasonal variations in species diversity and evenness in contrast to the stable values off the farming area. The oxygen deficient water mass below 2 ml/l In thi bottom layer during the summer stressed and depauperated the benthic community in the autumn of 1990. However, the benthic community did recover during the winter. It is postulated that the cyclic phenomenon of summer mortality followed by winter recovery may be a common characteristic in benthic communities subjected to a high level of organic pollution.

• Korean Journal of Ichthyology
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• v.31 no.4
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• pp.201-207
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• 2019

Temperature is one of the most important criteria considered in species preference for aquaculture. Acute drop in temperature during winter is a cause of disease and mass mortality in farmed fish. This study was carried out the low water temperature tolerance, oxygen consumption, hematologic and histological responses to use as basic data for the management of fish farming which frequently cause death due to winter water temperature drop. Low-lethal water temperature for 4 days of file fish Thamnaconus modestus (4day-LT₅₀) was 6.97℃ (6.69~7.27℃). Oxygen consumption rate decreased with decreasing water temperature, showing a significant difference between water temperatures. SOD activity increased significantly at 6℃ experimental group than control group (10℃) (p<0.05), but CAT did not show any significant difference between experimental temperatures (p>0.05). Cortisol increased with decreasing experimental water temperature compared to control group. Histological changes in the liver include decreased blood vessels in the blood vessels, proliferation of acid cells, condensation of the nucleus, atrophy of pancreatic exocrine gland cells, and enzyme source granules.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.93-101
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• 2000

This study was carried out to investigate the epidemiological prevalence of diseases from birth to weaning in 268 Koeran native calves which was delivered from three stock farm in Chonbuk area. We examined body weight gain, incidence rate of diseases and mortality rate in relation to age, season, environmental temperature and rearing management conditions for one year. The results of this experiment were as follows: Birth weight and body weight gain of Korean native calves born of primiparae were lower than those of multiparae. Body weight gain of diseased calves was lower than normal calves. Of 268 delivered calves, 242 calves(90.3%) were affected with gastronistestinal and/or respiratory diseases. The prevalence of the diseases were gastronitestinal disease(54.1%), gastronitestinal and respiratory disease(21.6%), and respiratory disease(14.5%). Of 242 diseased calves, 33 calves(13.6%) were occurred gastronitestinal disease and respiratory disease at different time respectively. Of 268 delivered calves, 126 calves were died(47%). The prevalence of the death were gastronitestinal disease(31.4%), gastronitestinal and respiratory disease(14.5%), and respiratory disease(1.1%). 81% of the diseases and 76.2% of the death were occurred in winter and a change of season(December to May). 59.1% of the diseases and 52.4% of the death were occurred at atmospheric temperatures below 1$0^{\circ}C$. 91.7% of the diseased calves and 96.8% of the dead calves were born of primiparae. 77.2% of the gastronitestinal disease were occurred within 2 weeks old, and the incidence was decreased with increasing age. Whereas the incidence of respiratory disease was incidence with ageing, and 69.2% of the respiratory disease were occurred between 2 weeks and 5 weeks old. And 62% of the gastronitestinal and respiratory disease wre occurred between 1 week and 3 weeks old. 65.1% of the dead calves were died within 2 weeks old. The morbidity and population mortality rate in each farm stock were 56.5%-104.9%, and 14.5%-64.2%, respectively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.2
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• pp.94-102
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• 1998

Temporal changes, density, calcimass, mode of occurrence, size-frequency histogram and survivorship curves were studied for the molluscan death assemblages on a macrotidal flat, Inchon, Korea. The living and death assemblages were compared on the basis of the taxonomic compositions and their numerical abundances. A total of 28 species (16 taxa in gastropods and 12 in bivalves) were identified. Most of the dead shells were the species inhabiting that intertidal mud flat. Species diversity was higher in gastropods than in bivalves. Seasonal variation of the calcimass was influenced by the mactrid bivalve, Mactra veneriformis. Shell-boring naticid gastropods preferred selecting the umbo areas of various valves. Size-frequency distribution and size-specific survivorship curves were analyzed for the dominant species. Survivorship curve of the tellinid bivalve, Morella rutila was convex-up in shape, which is congruent with the expected equilibrium condition but indicates higher mortality in winter. Whereas the survivorship curves of Mactra veneriformis and Reticunassa festiva were semi convex-up with dual modes, suggesting a disequilibrium due to the changes in recruitment and seasonal mortality. This study suggests that the dead shell assemblages may be useful in getting population information like live molluscan assemblages, if solved for several problems related to taphonomic processes.

• Journal of Preventive Medicine and Public Health
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• v.1 no.1
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• pp.1-8
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• 1968

This paper describes the incidence of transport accident for the period, 1955-1965. Transport accidents were classified into three categories, viz. railway(WHO Classification of Diseases, E-802), watercraft (E 550-E 858) and motor vehicle accidents(E810-E835, E840-E841, E844-E845). Crude data on the subject were collected from the various souces of Government Statistical Books including Statistical Year Books edited by the Central Office of Economic Planning Board, Annual Police Reports by the Ministry of Home Affairs, and the national and local associations for road traffic safety. From the data incidence and mortality rates by year, month and local province were computed and other variables relevant to the epidemiology of accidents were observed. The following summary could be drawn: 1. Death rates due to transport accidents per 100,000 population were 12.3 for 1955 and 9.7 for 1965. The incidence of injury due to the same cause were 34.0 for 1955 and 35.9 for 1965. 2. Death rates by transportation vehicle showed 9.0 due to motor vehicle accidents, 1.7 due to water-crafts, and 1.6 due to railway trains for 1955. In 1965 death rates were 6.0 due to motor vehicles, 1.2 to water-crafts and 2.4 to railway. 3. Seasonal distribution of transport accidents revealed that car accidents occur more frequently in spring and fall fall seasons while ship accidents do in winter and train accidents more in summer. 4. Both car and ship accidents slightly decreased during the past decade, 1955-1965, whereas the accidents of railway trains showed a tendency of increase. 5. Although the survey on railway accidents excluded the injuries of passengers or railway employees corresponding to WHO classification of diseases, E 801, due to inaccuracy of data, it is roughly estimated that the same number of casualities as the incidence among pedestrians or any other than passengers or employees assumed to be at work(E 802).